adts.HbaseClient.java Source code

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Here is the source code for adts.HbaseClient.java

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/**************************************************
Copyright (C) 2014  Raptis Dimos <raptis.dimos@yahoo.gr>
    
    
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
**************************************************/

package adts;

import java.io.BufferedReader;
import java.io.IOException;

import java.io.InputStreamReader;
import java.util.List;
import java.util.Random;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
import org.apache.hadoop.hbase.filter.FilterList;
import org.apache.hadoop.hbase.filter.SingleColumnValueFilter;
import org.apache.hadoop.hbase.rest.protobuf.generated.CellMessage.Cell;
import org.apache.hadoop.hbase.util.Bytes;

public class HbaseClient {
    //reads from the file with the most popular keywords(args[0]) and produces the suitable queries
    public static void main(String[] args) throws IOException {
        String[] keys = new String[5];
        int keywords_counter = 0;
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        Path inFile = new Path(args[0]);
        if (!fs.exists(inFile))
            System.out.println("Input file not found");
        if (!fs.isFile(inFile))
            System.out.println("Input should be a file");
        else {
            FSDataInputStream fsDataInputStream = fs.open(inFile);
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fsDataInputStream));
            String line;
            while (((line = bufferedReader.readLine()) != null) && (keywords_counter < 5)) {
                String[] array = line.split("\t");
                String keyword = array[0];
                System.out.println("Record :   " + keyword);
                keys[keywords_counter] = keyword;
                keywords_counter++;
            }
            bufferedReader.close();
            fs.close();

            Configuration config = HBaseConfiguration.create();
            HTable table = new HTable(config, "index");

            Random randomGenerator = new Random();
            for (int i = 0; i < 10; i++) {
                int randomInt = randomGenerator.nextInt(5);
                System.out.println("Random chosen keyword : " + keys[randomInt]);

                FilterList list = new FilterList(FilterList.Operator.MUST_PASS_ALL);
                SingleColumnValueFilter filter_by_name = new SingleColumnValueFilter(Bytes.toBytes("keyword"),
                        Bytes.toBytes(""), CompareOp.EQUAL, Bytes.toBytes(keys[randomInt]));
                //filter_by_name.setFilterIfMissing(true);
                list.addFilter(filter_by_name);

                Scan scan = new Scan();
                scan.setFilter(list);
                //scan.addFamily(Bytes.toBytes("keyword"));
                ResultScanner scanner = table.getScanner(scan);
                try {

                    for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
                        // print out the row we found and the columns we were looking for
                        byte[] cells = rr.getValue(Bytes.toBytes("article"), Bytes.toBytes(""));
                        System.out.println("Keyword " + keys[randomInt] + "belonging to article with md5 : "
                                + Bytes.toString(cells));
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    scanner.close();
                }

            }
            table.close();

        }

    }

}